It has been known for many years that borazine, (BHNH).sub.3, decomposes at high temperatures to provide a source of high purity boron nitride which is used as an alloying agent, in the manufacture of semiconductors and the like. However, methods for synthesizing borazine have not resulted in commercially significant yields or quantities.
Various methods of synthesis include the thermal decomposition of boron hydride-ammoniates, where B.sub.2 H.sub.6.2NH.sub.3 .fwdarw.B.sub.3 N.sub.3 H.sub.6 +H.sub.2, to provide yields of about 50%, but only in small quantities. Also, borazines are produced by reacting ammonium chloride and trichloroborane to form B-trichloroborazine which is reduced by lithium or sodium hydroborate. High purity borazine can be difficult to obtain because of residual chlorine impurities and complex purification procedures. Borazine can be produced without a solvent using a lithium borohydride and ammonium chloride by adhering to specific operating conditions to obtain up to 42% yields but only in quantities up to about 20-30 grams. Numerous other methods have been proposed, but none of the methods provide useful (pound) quantities of borazine.
Accordingly, it is an object of the present invention to provide a method for obtaining borzine in significantly greater quantities than previously available. It is a further object of the present invention to provide a method for the continuous or batch production of high purity borazine.